Parts Express - Tech Terms Glossary

Tech Terms Glossary

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Activity Detection: A feature used in multiplexers that uses video motion detection techniques to improve the camera update times. It can also give a relay closure.

Alarming: The ability of CCTV equipment to respond to an input signal, normally a simple contact closure. The response varies depending on equipment type.

Alkaline Cell/Battery: Modern, high-performance, non-rechargeable cells and batteries used in most modern "battery-driven" electrical and electronic consumer devices.

All-laminated Core: A special permalloy laminated core production process is used to reduce eddy current loss and improve the linear response range of the cartridge's magnetic circuit.

AM (Amplitude Modulation): Method of signal broadcast transmission used for radio.

AM Wide-Band Tuner: Picks up higher frequency range AM signals (from 1610kHz to 1710kHz) to receive newly allocated additional stations.

Ampere: The internationally accepted unit for the measurement of current flow (migrating electrons) in an electronic circuit. One ampere of current will flow through one ohm of resistance under the influence of one volt.

Angle Of View: The angular range that can be focused within the image size. Small focal lengths give a wide angle of view, and large focal lengths give a narrow field of view.

Anti-Skating Device: A carefully calibrated, adjustable device acting on the tone arm near its rotational center to counteract the natural tendency of the tone arm to move toward the center of the record, thereby holding the stylus centered in the record groove. Spring-mounted or suspended weight systems are typically used.

AP: Standard hole size for XLR-type and other audio connectors. Measures 7/8" diameter.

Aperture: The opening of a lens which controls the amount of light reaching the surface of the pickup device. The size of the aperture is controlled by the iris adjustment. By increasing the f stop number (f1.4, f1.8, f2.8, etc.) less light is permitted to pass to the pickup device.

Armature: The moving portion of a magnetic circuit. In a motor, the rotating center as opposed to the stationary stator. The coils in a MC cartridge; the magnet in a MM cartridge.

Aspect Ratio: The ratio of the picture frame width to the picture frame height in standard TV systems. It is 4 units horizontal over 3 units vertical.

Aspherical Lens: A lens designed with a non spherical shape so that it refracts the light passing through it to either lower the lens aperture so that it passes more light or decrease barrel distortion on wide angle lenses.

Attenuation: A decrease or loss in a signal.

Attenuator: used to lower the strength of a signal to better suit an application. In the case where a speaker is playing too loudly, an attenuator can be used to turn it down. In the case where a video signal is saturated, an attenuator can lower the strength to level out the picture.

Automatic Frequency Control (AFC): An electronic circuit used whereby the frequency of an oscillator is automatically maintained within specified limits.

Automatic Gain Control (AGC): An electronic circuit used by which the gain of a signal is automatically adjusted as a function of its input or other specified parameter.

Automatic Iris Lens: A lens in which the aperture automatically opens or closes to maintain proper light

Automatic Level Control (ALC): A feature on Automatic lris lenses (also known as the peak/average control). Adjusting this control allows the automatic iris circuitry to either take bright spots more into consideration (peak), bringing out detail in bright areas, or less into consideration (average) bringing out detail in shadows.

Automatic Power-Off: Automatically turns off the unit when no signal has been received for an extended period of time.

Automatic Preset Station Memory: Automatically scans the band width and presets available signals in the area in which you are traveling.

Automatic Reverse: Reverses the direction of the tape to play the second side when the end of the first side is reached. Allows repeated cassette playback for continuous listening.

Automatic Stop: Helps protect tape and prolong battery life. When tape reaches the end during playback, the unit stops and power shuts off automatically.

Automatic Tape Selector: Reads the tape being used to determine its formulation (metal, Cr02 or normal), then sets proper bias and equalization automatically.

Automatic Terminating: A feature where the equipment (ex. Monitor) automatically selects the correct termination depending on whether the video output BNC is connected.

Automatic White Balance: A feature on color camera that constantly monitors the light and adjusts its color to maintain white areas. A/V (Audio/Video): Refers to equipment that uses or controls audio and video signals.